Need Help Upgrading a computer for Gaming!

[Aaron Wilhite-1380637]

I'm am looking into upgrading my computer for better performance in gaming. i need all the advice I can get. ( I was actually thinking about purchasing the MSI AMD Radeon HD 7750)

Budget $140

Specs:
Processor- 2.4 Ghz Intel Quad Core
Ram- 3 GB
Graphics Card- NVIDIA 8600 GT
PSU- 300W

 

[Maygentria]

I'd suggest the AMD 7790, with the recent price drop it should be within budget!